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Lung Disorders in Children

We are basically going to talk about lung sounds and quickly look at aspects of stridor, cough, wheezing, cyanosis and tachypnea. Stridor, all of you know, is an inspiratory sound. Stridor is due to the narrowing of the extrathoracic airways. So this is primarily upper airways, larynx, things along those lines. What are the most common causes? In infancy, if one has an acute onset of stridor, viral croup is probably statistically far and away the most common.

Basically, I think rather than memorizing these lists, I think the thing to think about is upper airway problems are things that could cause chronic stridor. If there are questions about what might be a cause of chronic stridor.

For the older child or adolescent, the list is a bit more complex. Viral croup is still a possibility in younger children. Epiglottitis can occur under five, but one can start to get other more exotic things like retropharyngeal abscesses, peritonsillar abscesses, trauma and other sorts of things. Foreign body is always on the list. Chronic stridor, subglottic stenosis.

Chronic cough; obviously cough is a nonspecific symptom that can be caused by a number of things. If we look at frequent causes of cough in infants, again leading the list is probably aspiration. Secondly would be asthma and, in contradistinction to what they taught when I was in medical school, asthma can occur in infants and start fairly early in infancy. Cystic fibrosis, especially if the child is a Caucasian.

Wheezing in infancy; wheezing of course is an expiratory sound and indicative of intrathoracic airway obstruction, specifically intrapulmonary airway obstruction. So if we look at causes of wheezing in infancy, acute onset wheezing, bronchiolitis, one could have a first time asthma episode, and foreign body basically lead the list. Chronic wheezing; asthma is still a possibility. Recurrent aspiration is very common. If an infant was born prematurely.

Wheezing in the older child or adolescent; again, asthma far and away the most common. Foreign body still can occur, other types of allergic reactions and psychogenic. And psychogenic here has the same comments that we discussed for psychogenic cough. Chronic wheezing; asthma, foreign body, CF, some anatomic problem, and psychogenic.

Cyanosis. Cyanosis, of course as you all know, is blueness of the skin. Usually seen mostly on the lips, around the mouth, fingers, etc. Cyanosis is present when there are five grams per deciliter of unsaturated hemoglobin. Now, normal mixed venous oxygen saturation for all of us in the room is 75%.

Congenital anomalies of the lung. What Iím going to pick out here is some that have been favorites of the Board, and also some of the more common abnormalities. So laryngomalacia, tracheal anomalies, lobar emphysema, sequestration and congenital diaphragmatic hernias. Laryngomalacia is actually very common. It is basically due to decreased cartilaginous support of the larynx. Is usually presents shortly after birth with a high-pitched inspiratory stridor and this is worse during crying or agitation.

Tracheal anomalies. The normal trachea has 22 rings which are not fused posteriorally. So the tracheal ring, if you will, is actually C-shaped with a membrane in the back. Tracheomalacia - which basically means soft trachea - results in a segment, one or more segments lacking normal cartilaginous support. So if you have floppy cartilaginous support it basically means that during exhalation, usually, the trachea will collapse at that point causing symptoms of airway obstruction. It could also cause stridor but more commonly it causes wheezing. Tracheal stenosis, on the other hand, may be due to complete tracheal rings in some cases.